Medical devices comprising catheter shafts and catheter balloons are used in an increasingly widening variety of applications including vascular dilatation, stent delivery, drug delivery, delivery and operation of sensors and surgical devices such as blades, and the like. The desired physical property profile for the balloons used in these devices varies according to the specific application, but for many applications a high strength robust balloon is necessary and good softness and trackability properties are highly desirable.
Commercial high strength balloons having wall strengths in excess of 20,000 psi have been formed of a wide variety of polymeric materials, including PET, nylons, polyurethanes and various block copolymer thermoplastic elastomers. U.S. Pat. No. 4,490,421 Levy, and U.S. Pat. No. 5,264,260, Saab, describe PET balloons. U.S. Pat. No. 4,906,244, Pinchuk et al, and U.S. Pat. No. 5,328,468, Kaneko, describe polyamide balloons. U.S. Pat. No. 4,950,239, Gahara, and U.S. Pat. No. 5,500,180, Anderson et al describe balloons made from polyurethane block copolymers. U.S. Pat. No. 5,556,383, Wang et al, and U.S. Pat. No. 6,146,356, Wang et al, describe balloons made from polyether-block-amide copolymers and polyester-block-ether copolymers. U.S. Pat. No. 6,270,522, Simhambhatla, et al, describes balloons made from polyester-block-ether copolymers of high flexural modulus. U.S. Pat. No. 5,344,400, Kaneko, describes balloons made from polyarylene sulfide. U.S. Pat. No. 5,833,657, Reinhart et al, describes balloons having a layer of polyetheretherketone. All of these balloons are produced from extruded tubing of the polymeric material by a blow-forming radial expansion process. U.S. Pat. No. 5,250,069, Nobuyoshi et al, U.S. Pat. No. 5,797,877, Hamilton et al, and U.S. Pat. No. 5,270,086, Hamlin, describe still further materials which may be used to make such balloons.
A particular application which has a very high pressure requirement is reopening of stenoses which develop at or in long-term shunt, ports or grafts employed for repeated blood access, for instance with dialysis patients. Such stenoses are often highly calcified and essentially must be subjected to very high pressure for successful treatment. Moreover, frequently the vessels into which the access devices are connected are quite large. Consequently there is a need for balloons whose pressure profile allows for use of pressures in excess of 20 atm at balloon diameters which can exceed 5 mm.
Fiber reinforced balloons have been known for use in angioplasty and similar applications. U.S. Pat. No. 4,896,669, Behate, U.S. Pat. No. 4,706,670, Andersen, U.S. Pat. No. 5,647,848, Jorgensen, all show balloons formed with a fiber web reinforcement, but the rest condition of the balloon is straight. In some cases the balloon is a portion of the catheter tube in which a web pattern such as a braid has been modified to allow for elastic radial expansion to a diameter determined by the angle of the fiber reinforcements. The web is encased in an elastomeric polymer material.
U.S. Pat. Nos. 5,201,706, and 5,330,429, Noguchi, describe a laminate balloon which uses a release agent between a web layer and an inner layer of the balloon structure.
U.S. Pat. No. 5,827,289, Reiley, shows a mesh 170 “embedded or laminated and/or winding” used to form a neck on the balloon and a second mesh 170a used to form a tapered base. As understood, the mesh conforms the underlying balloon to the mesh shape, rather than conforming the mesh to a tapered section of a balloon.
U.S. Pat. No. 6,156,254, Andrews, shows a balloon formed by braiding fiber onto an unoriented tube and encasing the braid in same material; longitudinally stretching the braided tube onto a rod of smaller diameter; heating the tube ends, but not the middle; and then releasing the stretch force so the center recovers to formed diameter but the ends remain at the stretched diameter. The patent states that the fibers should be bonded to the wall material so that they do not move or slide significantly with respect to the wall material. Soft wall materials are described as balloon materials: polyurethane, SBS block copolymer, butadiene-acrylonitrile block copolymer. As an alternative, the inner tube layer may be PET or PVC, while the outer encasement material is polyurethane. In an alternative method of making the balloon, a polyurethane film is cast from dispersion onto an inflatable balloon form, the fiber braid is applied to the film layer and an outer layer of polyurethane is applied. The balloon is removed from the form by deflating the form.